The invention relates to a fluid system for an oscillating-piston engine having at least two oscillating pistons arranged in a spherical housing and revolving together around an axis of revolution arranged in the housing centre, each of them having two opposing piston arms and which when revolving, mutually perform reciprocating oscillating movements in opposite directions about an oscillating axis perpendicular to the axis of revolution, wherein guide members attached to at least two piston arms engage in at least one guide groove formed in the housing and serving to control the oscillating movements.
These oscillating-piston engines belong to the type of combustion engines in which the combustion strokes of intake, compression, expansion and exhaust of the fuel mixture according to the Otto or Diesel four-stroke method with externally-supplied ignition and self-ignition, respectively, are achieved by oscillating movements of the revolving pistons between two end positions.
Such an oscillating piston engine known from WO 2005/098202 A1 has fluid feeds from the inner piston side to the loose spherical or ellipsoidal rotational bodies serving as guide members. Instead of these loose guide members, radially rotatable rollers connected fixed to the pistons can also exist as they are described, for example, in U.S. Pat. No. 3,075,056 and WO 03/067033. For these guide members, lubrication is also provided or necessary, respectively. For the first one of the above-mentioned oscillating-piston engines, furthermore, an internal cooling by means of fluid is described, in which behind the side faces as well as behind the inner piston faces, which enclose the working chambers, cavities filled with fluid are arranged, which heat up by the heat transfer coming from the inner faces of the working chambers and transfer this heat by means of fluid circulation to the tank and, if necessary, to fluid-cooling devices. In addition, the bearings of the revolving oscillating axis and the sealing elements running on the inner side of the housing must be lubricated. The fluid system is supposed to protect machine parts rubbing against each other by means of appropriate lubrication against excessive wear, to improve the efficiency by reducing the resistance to rotation, and, if necessary, to additionally ensure cooling by heat dissipation by means of heating up a fluid and dissipation from the engine.